iOS 13.4 (build 17E5255a) is an official Apple over-the-air update for the iPhone 6s+, released on 2020-03-10T17:21:32Z. The update package is 77.86 MB. This is a delta (partial) update that requires 13.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5355df726daa438ccab3b3773e6b9d4523f7046d.zip.